1. Field of the Invention
The present invention relates to a vehicle-use lamp fixture and braking indicator mechanism, and more particularly to a lamp fixture and braking indicator mechanism for a vehicle in which the light does not become dim due to fogging of a rear window glass, the lamp lights up simultaneously with braking and the light is easily recognized by the drivers of the cars following the vehicle.
2. Description of the Prior Art
Presently, stop lamps (brake lamps) are provided on the automotives, etc., as one of vehicle-use lamp fixtures to inform the vehicles following them that they are being braked under running.
Generally, the installation positions of the stop lamps are on a chassis panel located above a rear bumper; that is, on a rear end panel. When a brake pedal is stepped on, the stop lamp lights up to inform the vehicles following it that it is being braked. Since the aforementioned stop lamps are located above the rear bumper, they can be seen without hindrance by the vehicle that is at the immediate rear of the vehicle itself. Recently, in order that the braking can be distinctly recognized not only by the second car following it but also by other following cars, a `high-mount` stop lamp besides the normal stop lamps is being provided at a position much higher than the normal stop lamps. An example of this `high-mount` stop lamp 101 is shown in FIG. 1, where a lamp fixture body 107 is arranged in such a way that a lens surface 105 of the lamp 101 faces a rear window glass plate 103. The surrounding of the lens surface 105 is enclosed by a lamp case 109 which is in contact with the glass plate 103. Such a construction is, for example, mentioned in Japanese Patent Publication No. 57-74237.
Regarding the high-mount stop lamp 101, if the irradiated light from the lamp leaks into the passenger room of the vehicle by reflecting on the window glass, then the lamp is in violation of the regulations. Therefore, the surroundings of the lens surface 105 is enclosed in the lamp case 109 made of a material which can cut-off light to form an enclosed space 111 between the glass plate 103 and the lens surface 105.
Although the rear window glass plate 103 is wired with a defogger heat-wire to prevent fogging, the lamp case 109 is located such that it avoids the heat-wire, because it may get, depending upon its material, if it comes in direct contact with the heat-wire.
Consequently, as the closed space 111 surrounded by the lamp case 109 is placed outside the area of the defogger heat-wire, the glass surface 113 of the glass plate 103 within the closed space 111 gets easily fogged. However, as this is a closed space, the fog cannot be eliminated, and for this reason the light permeability of lens surface 105 becomes poor. As a result, the recognizable distance of the stop lamp becomes remarkably short and this is undersirable from the point of safety.